I don’t have a solution to your problem but, having come across it, wanted to share my experience with ethanol. I have a 2004 Hyundai Santa Fe, 3.5L, 4WD. Virtually every tank of gas in this vehicle; now with 82k miles; has contained 10% ethanol, since, like you said, that is all that is available in many locations. My vehicle has always run great; I still have the original spark plugs and have not had injectors cleaned (I do add a bottle of Amsoil PI to gas every 5k). I get 24 mpg (highway average). When my Hyundai was only a year or so old I experimented (after some research to be sure I would not harm the engine) with 85% ethanol. I filled with this blend on three different, but not subsequent, occasions. My car ran normally but I think the computer was confused because my check engine light came on. It went out again after burning several gallons of gasoline (with 10% ethanol). My fuel economy dropped about 10% based, I guess, on its lower BTU content/Gasoline Gallon Equivalent. The E85, at that time, was quite a bit less expensive than gasoline so it more than balanced out. The reason I have not done this since, besides the computer confusion; which I could have possibly reprogrammed; is because ethanol, at that level, is corrosive. Vehicles designed for E85 have the components that come in contact with fuel made of, or lined with, special corrosion-resistant materials. I would like to hear what Click and Clack have to say on this subject…or anyone else out there with knowledge or an experience with ethanol.